Phosphonated mercaptals and mercaptoles



United States Patent Ofi Fice 3,373,23fi Patented Mar. 12, 1968 3,373,230 PHOSPHUNATED MERCAPTAL AND MERCAPTOLES Edward Nelson Walsh, Chicago Heights, Ill., and David J.

Broadbent, San Jose, Calif., assignors to stander Chernical Company, New York, N.Y., a corporation of Delaware No Drawing. Filed July 9, 1964, Ser. No. 381,512

Claims. (Cl. 260949) ABSTRACT 0F THE DISCLOSURE Phosphon'ated mercaptals and mercaptoles corresponding to the formula in which alkylene means a divalent saturated aliphatic having from 1 to 3 carbon atoms; X is oxygen or sulfur; R is lower alkyl or phenyl; R is lower alkyl; R and R are independently lower alkyl, phenyl or halo-substituted phenyl; and R is lower alkyl or hydrogen. The above compounds are effective as pesticides. Representative compounds are O-ethyl-S-[2,2-bis(ethylthio)propyl-1}ethylphosphonodithioate, O-ethyl-S- 2,2-bis ethylthio propyl- 1]methylphosphonodithioate, O-ethyl-S- [2,2-bis (4-chlorophenyDpropyl-l]methylphosphonodithioate and O-ethyl- S-[2,2-bis(butylthio)propyl-1]ethylphosphonodithioate.

The present invention is concerned with a novel group of phosphonated mercaptals, their method of preparation and use as pesticides.

The novel compounds may be represented by the general formula;

wherein al-kylene means a divalent saturated aliphatic having from 1 to 3 carbon atoms; X is selected from the group consisting of sulfur and oxygen; R is lower alkyl or phenyl; R is lower alkyl; R and R are independently selected from the group consisting of lower alkyl, phenyl, and halo-substituted phenyl; and R is lower alkyl or hydrogen. V

The lower alkyl radicals which are suitable for R, R, R R and R arethe straight and branched chain aliphatic radicals having from 1 to 8 carbon atoms and include, for example, methyl, ethyl, propyl, isopropyl, amyl, Z-ethylhexyl, and the like. The halo-substituted phenyl included under the definition of R are the chloro, bromo, or fiuoro substituted, and preferably chloro.

The general process for preparing the compounds of the invention may be illustrated by the following equation:

wherein all of the substituents are the same as defined hereinbefore. The reaction is preferably carried out in the presence of a stron acid catalyst such as boron trifluoride etherate or gaseous HCl; an inert solvent such as benzene, ether, and the like may be used, but is not required. Reaction temperatures, while they need not be critically controlled during these reactions, are normally maintained between about 0 C. and 108 (3.; preferably between 10 C. and 50 C. Higher temperatures may cause appreciable side products to form due to an attack by the acid catalyst.

In the preferred process, the rnercaptans or 2 moles of a single mercaptan (where R and R are to be identical) are added to the phosphonated aldehyde or ketone before addition of the catalyst. When R and R are to be different radicals, one mercaptan may be first added, then some of the catalyst, and after the first reaction is fairly well along, usually within ten to thirty minutes, the same order of addition (i.e., reactant first, then catalyst) may be used for a reaction of the second mercaptan. Although the order of addition may have some slight effect 'on yields, it is not a critical feature of the invention. Recovery of a pure phosphonated mercaptal product from the reaction mixture requires washing the reaction mixture to remove side products, unreacted compounds, and the acid catalyst. For convenience, the reaction mixture may first be dissolved in an inert organic solvent such as benzene or ether. The washing may be accomplished with water or aqueous sodium hydroxide, sodium carbonate, sodium sulfate solutions (to remove the unreacted aldehyde or ketone), and the like. Normally, the reaction will yield between and of the theoretically predicted amount of phosphonated mercaptal.

The general process for preparing the novel phosphonated aldehyde or kctone intermediate shown in the above equation may be illustrated by the following reaction:

wherein halo means a halogen radical such as chlorine, bromine, or iodine; Y means an alkali metal and includes for example, sodium and potassium; alkylene means a divalent saturated aliphatic having from 1 to 3 carbon atoms; R and R are lower alkyl; X is oxygen or sulfur; and R is an alkyl of from 1 to 3 carbon atoms or hydrogen. Reaction temperatures, while they need not be critically controlled during these mildly exothermic reactions are normally maintained between about 0 C. and 100 C. preferably between 20 C. and 50 C. A specific example of a compound prepared by the aforementioned process is illustrated in US. patent application Ser. No. 381,509 dated July 9, 1964. Y

The following examples illustrate specific compounds of the invention and their method of preparation, but should not be construed as unduly limiting the broader aspects of the invention.

Example 3) 2 5 (S) 2 a) 2 5)2 To 8.0 grams of (CH )(C H O)P(S)-S CH C(0)CH contained in a reactor flask fitted with a stirrer and ther= mometer was added 20 ml. of ethanthiol. Then 0.5 ml. of boron trifluoride etherate was added to catalyze the reaction. The temperature was maintained between 27 C. and 32 C., and the reaction mixture stirred for 18 hours. The mixture was dissolved in 100 cc. of ethyl ether, twice washed with 50 cc. of water, filtered and concentrated to 60 C. under 1 mm. of Hg. The concentrated product consisted of 10.2 grams (85% ield) of O-ethyl- S- [2,2 bis(ethylthi0)propyl-1]methylphosphonodithioate having an index of refraction N =1.5563, and analysis 3 V 4 of 9.9% P and 38.9% S as compared to 9.8% P and INSECT SPECIES 40.3% S, theoretical. Housefly Musca domestica (Linn).

Example 2 American cockroach Periplaneta americana (Linn).

Spotted milkweed bug- Oncopeltus fasciatus (Dallas). H3)(ClH5 MITE SPECIES Two-spotted mite Tetranychus telarz'us (Linn.).

TABLE I.-MORTALITY OF REPRESENTATIVEflSfllgEgfIES OF COMMON INSECT ORDERS AND MITES Compound T. telarius (Example number, M. domesiica P. americtma O. fasct'atu-s see supra) Post embryonic Nymphs Eggs Systemic 0.01 0.01 0.05 8p.p.m. 0. 01 0. 01 0.1 0. 005 0. 005 3 .m. 0. 05 0.08 0.1

To 5.3 grams of In the screening tests for the insect species of Table I, c, I from ten to twenty-five insects were caged in cardboard (CH3)(C2H5O)P(S) S H2C(O)CH3 mailing tubes 3%" in diameter and 2% tall. The cages COlflfllllfid in a reactor flask fitted Wdth a stirrer and therwere upplied with cellophane bottoms and creen t0p mometel' was added gr 31115 of 4-chlofobenzenethiol- Food and water were supplied to each cage. Dispersions The reactants were dissolved in 20 ml. of ethyl ether; 3 of th t st cumpounds were prepared by dissolving oneml. of boron trifluoride etherate was a e t catalyze half gram of the toxic material in 10 ml. of acetone. This the Ieaotion- The 'P Was maintained between solution was then diluted with water containing 0.0175% and Thell 5 grams of 2 4 added v./v. Sponto 221, an emulsifying agent, the amount of and the temperature rose to 28 C. The reaction mix u e water being sufiicient to dilute the active ingredients to was stirred for 18 hours and then transferred to a s p a concentration of 0.1% or below. The test insects were iflg funnel and dissolved in ethyl e The then sprayed with this dispersion. After twenty-four and mixture was washed twice with 50 ml. of water, counter- 30 seventy-two hours, counts were made to determine living washed with 50 cc. of ethyl ether and dried over Na 'SO nd dead i sects,

After concentrating to 60 C. under 1 mm. Hg the prod- Some of the compounds which showed high mortality uct consisted of 12.2 grams (100% yield) of O-ethyl-S- on housefl-ies in the screening test were bioassayed on M. p ynp py l] hylphosphonodidomestica. In this test, a known quantity of the'toxicant thioate having an index of refraction N =l.6l-60 and was placed in a confined area. The same cages were emanalysis of 5.7% P, 25.4% S, and 14.1% C1 as compared ployed as for the fly screening test. A weighed amount of to 6. 4% P, 26.5% S, and 14.7% C1, theoretical. the toxicant was placed in Pyrex petri dishes having a The fOHOWing pecific compounds were prepared by a surface area of 18.8 sq. centimeters along with 1 ml. of procedure substantially in accordance with those of Exacetone. After the solvent was evaporated by air-drying, a amples land 2: 40 cage containing groups of twenty-five female flies, three Example 3 to five days old, was placed over the residue. Counts of I living and dead insects were made forty-eight hours after (OHQ)(CZH5O)P(S) S CH2C(SC4H9)2CH3 initiation of the test. Y [2,2 i y )p py limethylphos- It has been further found that the compounds of the phonodithmatepresent invention are excellent systemic miticides. In Example 4 testing for systemic action, pinto bean plants were placed ;(C2H5)(\C2H5O)P(S) OH2C(Sc2I I5)2CH3 in bottles containing 200 Of the test solution and were held in place with cotton plugs. Only the roots 0 ethyl S [22'b1s(eth$1th1)PTOPYIJI]ethylphos' were immersed. The solutions were prepared by dissolv- Phonodifliioateing the candidate miticide in acetone or other suitable Example 5 solvent and then diluting with tap water. The final ace- (C2H5),(C2,H50)P(S) S ;CHZC(SC4HQ)ZCH3 tone concentration of the solution was never allowed to exceed 1% and the toxicant was initially tested at a con- 0 ethyl S [zt'zbis(butykhiomropyl uethylphos' centration of 100 p.p.m. As soon as the plants were Phonodithioate' placed in the solution they were infested with mites. Example 6 Mortalities of post embryonic, nymph, and ovicid'al (-C H )'(C H O)P(S) -S-CH O(SC H CH forms were determined seven days after initiation of the test. g ggii gg' '[zz'blswutylthlwpropyl'l1pheny1phos' Although the above tests were accomplished with p 1 E l 7 aqueous dispersions, the toxic compounds can also be xamp 8 used commercially in the form of aqueous solutions when (C5135)(CQH5O)PI(S)SCHQC(SCZH5)2CH3 appreciably soluble, Eton-aqueous solutions, hwettable v powders, vapors, and usts as best suited to t e condig g fi xi i bls ethy1thlo propy1 11p henylphos tions of use. In many applications fillers will be incorporated with the toxic compounds. For more specialized The new compounds have been found to be generally application, the material may even be used in its pure,

active as pesticides, but exhibit exceptionally high activity d f with the two-spotted mite, Tetranychus telarius (Linn). um lute Pesticidal activity for the phosphonated mercaptals is i R 56mm the term R Intended m the illustrated in Table I wherein the 50% ,(LD 50) restricted sense generally recogmzed 1n the art asap- .among the pest Species is reported for a Specified quantity plying to the lower forms of life customarily controlled of a did t o d expressed i micrograms by chemical means 'and excluding the higher animals, herein termed the bioassay test), or for a percentage conthe Vertebrates, for p rodents, 1311115, and larger centration in aqueous dispersion (herein termed the forms w c re more commonly Controlled by mechanscreening test). a 7 ical means such as traps. It will be apparent to one skilled in the art that the toxic activity demonstrated hereinbefore on various test species is indicative of activity with species and orders not specifically shown.

The foregoing description is given for clearness of understanding only and no unnecessary limitations should 5 be understood therefrom, as modifications will be obvious to those skilled in the art.

We claim:

1. A compound having the formula:

wherein alkylene means a divalent saturated aliphatic 15 6 2. O ethyl S [2,2-bis(ethylthio)propyl-1]ethylphosphonodithioate.

3. O ethyl S [2,2-bis(ethylthio)propyl-1] methylphosphonodithioate.

4. O ethyl S [2,2-bis(4-chlorophenyl) propyl- 1] methylphosphonodithioate.

5. O ethyl S [2,2- bis( butylthio)propyl-1] ethylphosphonodithioate.

References Cited UNITED STATES PATENTS 4/1959 Schrader 260948 X 9/1963 Walsh et a1. 26'0'948 X OTHER REFERENCES Reid: Organic Chemistry of Bivalent Sulfur, vol. 3, page 320 (1960), Chemical Publishing Co., Inc., New York.

20 CHARLES B. PARKER, Primary Examiner.

A. H. SUTTO. Assistant Examiner. 

